blob: df2ef15d03d256157c70b4a8b8be0b751d1dfab1 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/inode.c
3 *
4 * (C) 1997 Linus Torvalds
5 */
6
Linus Torvalds1da177e2005-04-16 15:20:36 -07007#include <linux/fs.h>
8#include <linux/mm.h>
9#include <linux/dcache.h>
10#include <linux/init.h>
11#include <linux/quotaops.h>
12#include <linux/slab.h>
13#include <linux/writeback.h>
14#include <linux/module.h>
15#include <linux/backing-dev.h>
16#include <linux/wait.h>
17#include <linux/hash.h>
18#include <linux/swap.h>
19#include <linux/security.h>
20#include <linux/pagemap.h>
21#include <linux/cdev.h>
22#include <linux/bootmem.h>
Robert Love0eeca282005-07-12 17:06:03 -040023#include <linux/inotify.h>
Christoph Hellwigfc33a7b2006-01-09 20:52:17 -080024#include <linux/mount.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025
26/*
27 * This is needed for the following functions:
28 * - inode_has_buffers
29 * - invalidate_inode_buffers
Linus Torvalds1da177e2005-04-16 15:20:36 -070030 * - invalidate_bdev
31 *
32 * FIXME: remove all knowledge of the buffer layer from this file
33 */
34#include <linux/buffer_head.h>
35
36/*
37 * New inode.c implementation.
38 *
39 * This implementation has the basic premise of trying
40 * to be extremely low-overhead and SMP-safe, yet be
41 * simple enough to be "obviously correct".
42 *
43 * Famous last words.
44 */
45
46/* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */
47
48/* #define INODE_PARANOIA 1 */
49/* #define INODE_DEBUG 1 */
50
51/*
52 * Inode lookup is no longer as critical as it used to be:
53 * most of the lookups are going to be through the dcache.
54 */
55#define I_HASHBITS i_hash_shift
56#define I_HASHMASK i_hash_mask
57
Eric Dumazetfa3536c2006-03-26 01:37:24 -080058static unsigned int i_hash_mask __read_mostly;
59static unsigned int i_hash_shift __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -070060
61/*
62 * Each inode can be on two separate lists. One is
63 * the hash list of the inode, used for lookups. The
64 * other linked list is the "type" list:
65 * "in_use" - valid inode, i_count > 0, i_nlink > 0
66 * "dirty" - as "in_use" but also dirty
67 * "unused" - valid inode, i_count = 0
68 *
69 * A "dirty" list is maintained for each super block,
70 * allowing for low-overhead inode sync() operations.
71 */
72
73LIST_HEAD(inode_in_use);
74LIST_HEAD(inode_unused);
Eric Dumazetfa3536c2006-03-26 01:37:24 -080075static struct hlist_head *inode_hashtable __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -070076
77/*
78 * A simple spinlock to protect the list manipulations.
79 *
80 * NOTE! You also have to own the lock if you change
81 * the i_state of an inode while it is in use..
82 */
83DEFINE_SPINLOCK(inode_lock);
84
85/*
Ingo Molnarf24075b2006-03-23 03:00:34 -080086 * iprune_mutex provides exclusion between the kswapd or try_to_free_pages
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 * icache shrinking path, and the umount path. Without this exclusion,
88 * by the time prune_icache calls iput for the inode whose pages it has
89 * been invalidating, or by the time it calls clear_inode & destroy_inode
90 * from its final dispose_list, the struct super_block they refer to
91 * (for inode->i_sb->s_op) may already have been freed and reused.
92 */
Adrian Bunkbdfc3262006-03-25 03:06:56 -080093static DEFINE_MUTEX(iprune_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070094
95/*
96 * Statistics gathering..
97 */
98struct inodes_stat_t inodes_stat;
99
Christoph Lametere18b8902006-12-06 20:33:20 -0800100static struct kmem_cache * inode_cachep __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101
102static struct inode *alloc_inode(struct super_block *sb)
103{
Christoph Hellwigf5e54d62006-06-28 04:26:44 -0700104 static const struct address_space_operations empty_aops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 static struct inode_operations empty_iops;
Arjan van de Ven99ac48f2006-03-28 01:56:41 -0800106 static const struct file_operations empty_fops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 struct inode *inode;
108
109 if (sb->s_op->alloc_inode)
110 inode = sb->s_op->alloc_inode(sb);
111 else
Christoph Lametere94b1762006-12-06 20:33:17 -0800112 inode = (struct inode *) kmem_cache_alloc(inode_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113
114 if (inode) {
115 struct address_space * const mapping = &inode->i_data;
116
117 inode->i_sb = sb;
118 inode->i_blkbits = sb->s_blocksize_bits;
119 inode->i_flags = 0;
120 atomic_set(&inode->i_count, 1);
121 inode->i_op = &empty_iops;
122 inode->i_fop = &empty_fops;
123 inode->i_nlink = 1;
124 atomic_set(&inode->i_writecount, 0);
125 inode->i_size = 0;
126 inode->i_blocks = 0;
127 inode->i_bytes = 0;
128 inode->i_generation = 0;
129#ifdef CONFIG_QUOTA
130 memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
131#endif
132 inode->i_pipe = NULL;
133 inode->i_bdev = NULL;
134 inode->i_cdev = NULL;
135 inode->i_rdev = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 inode->dirtied_when = 0;
137 if (security_inode_alloc(inode)) {
138 if (inode->i_sb->s_op->destroy_inode)
139 inode->i_sb->s_op->destroy_inode(inode);
140 else
141 kmem_cache_free(inode_cachep, (inode));
142 return NULL;
143 }
144
145 mapping->a_ops = &empty_aops;
146 mapping->host = inode;
147 mapping->flags = 0;
148 mapping_set_gfp_mask(mapping, GFP_HIGHUSER);
149 mapping->assoc_mapping = NULL;
150 mapping->backing_dev_info = &default_backing_dev_info;
151
152 /*
153 * If the block_device provides a backing_dev_info for client
154 * inodes then use that. Otherwise the inode share the bdev's
155 * backing_dev_info.
156 */
157 if (sb->s_bdev) {
158 struct backing_dev_info *bdi;
159
160 bdi = sb->s_bdev->bd_inode_backing_dev_info;
161 if (!bdi)
162 bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
163 mapping->backing_dev_info = bdi;
164 }
Al Viroe6c6e642006-10-10 22:48:47 +0100165 inode->i_private = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 inode->i_mapping = mapping;
167 }
168 return inode;
169}
170
171void destroy_inode(struct inode *inode)
172{
Eric Sesterhennb7542f82006-04-02 13:38:18 +0200173 BUG_ON(inode_has_buffers(inode));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 security_inode_free(inode);
175 if (inode->i_sb->s_op->destroy_inode)
176 inode->i_sb->s_op->destroy_inode(inode);
177 else
178 kmem_cache_free(inode_cachep, (inode));
179}
180
181
182/*
183 * These are initializations that only need to be done
184 * once, because the fields are idempotent across use
185 * of the inode, so let the slab aware of that.
186 */
187void inode_init_once(struct inode *inode)
188{
189 memset(inode, 0, sizeof(*inode));
190 INIT_HLIST_NODE(&inode->i_hash);
191 INIT_LIST_HEAD(&inode->i_dentry);
192 INIT_LIST_HEAD(&inode->i_devices);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800193 mutex_init(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 init_rwsem(&inode->i_alloc_sem);
195 INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC);
196 rwlock_init(&inode->i_data.tree_lock);
197 spin_lock_init(&inode->i_data.i_mmap_lock);
198 INIT_LIST_HEAD(&inode->i_data.private_list);
199 spin_lock_init(&inode->i_data.private_lock);
200 INIT_RAW_PRIO_TREE_ROOT(&inode->i_data.i_mmap);
201 INIT_LIST_HEAD(&inode->i_data.i_mmap_nonlinear);
202 spin_lock_init(&inode->i_lock);
203 i_size_ordered_init(inode);
Robert Love0eeca282005-07-12 17:06:03 -0400204#ifdef CONFIG_INOTIFY
205 INIT_LIST_HEAD(&inode->inotify_watches);
Ingo Molnard4f9af92006-03-23 03:00:30 -0800206 mutex_init(&inode->inotify_mutex);
Robert Love0eeca282005-07-12 17:06:03 -0400207#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208}
209
210EXPORT_SYMBOL(inode_init_once);
211
Christoph Lametere18b8902006-12-06 20:33:20 -0800212static void init_once(void * foo, struct kmem_cache * cachep, unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213{
214 struct inode * inode = (struct inode *) foo;
215
Christoph Lameter50953fe2007-05-06 14:50:16 -0700216 if (flags & SLAB_CTOR_CONSTRUCTOR)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 inode_init_once(inode);
218}
219
220/*
221 * inode_lock must be held
222 */
223void __iget(struct inode * inode)
224{
225 if (atomic_read(&inode->i_count)) {
226 atomic_inc(&inode->i_count);
227 return;
228 }
229 atomic_inc(&inode->i_count);
230 if (!(inode->i_state & (I_DIRTY|I_LOCK)))
231 list_move(&inode->i_list, &inode_in_use);
232 inodes_stat.nr_unused--;
233}
234
235/**
236 * clear_inode - clear an inode
237 * @inode: inode to clear
238 *
239 * This is called by the filesystem to tell us
240 * that the inode is no longer useful. We just
241 * terminate it with extreme prejudice.
242 */
243void clear_inode(struct inode *inode)
244{
245 might_sleep();
246 invalidate_inode_buffers(inode);
247
Eric Sesterhennb7542f82006-04-02 13:38:18 +0200248 BUG_ON(inode->i_data.nrpages);
249 BUG_ON(!(inode->i_state & I_FREEING));
250 BUG_ON(inode->i_state & I_CLEAR);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251 wait_on_inode(inode);
252 DQUOT_DROP(inode);
Christoph Hellwigacb0c852007-05-08 00:25:52 -0700253 if (inode->i_sb->s_op->clear_inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254 inode->i_sb->s_op->clear_inode(inode);
Theodore Ts'oeaf796e2006-09-27 01:50:48 -0700255 if (S_ISBLK(inode->i_mode) && inode->i_bdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 bd_forget(inode);
Theodore Ts'o577c4eb2006-09-27 01:50:49 -0700257 if (S_ISCHR(inode->i_mode) && inode->i_cdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 cd_forget(inode);
259 inode->i_state = I_CLEAR;
260}
261
262EXPORT_SYMBOL(clear_inode);
263
264/*
265 * dispose_list - dispose of the contents of a local list
266 * @head: the head of the list to free
267 *
268 * Dispose-list gets a local list with local inodes in it, so it doesn't
269 * need to worry about list corruption and SMP locks.
270 */
271static void dispose_list(struct list_head *head)
272{
273 int nr_disposed = 0;
274
275 while (!list_empty(head)) {
276 struct inode *inode;
277
Pavel Emelianovb5e61812007-05-08 00:30:19 -0700278 inode = list_first_entry(head, struct inode, i_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 list_del(&inode->i_list);
280
281 if (inode->i_data.nrpages)
282 truncate_inode_pages(&inode->i_data, 0);
283 clear_inode(inode);
Artem B. Bityuckiy4120db42005-07-12 13:58:12 -0700284
285 spin_lock(&inode_lock);
286 hlist_del_init(&inode->i_hash);
287 list_del_init(&inode->i_sb_list);
288 spin_unlock(&inode_lock);
289
290 wake_up_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 destroy_inode(inode);
292 nr_disposed++;
293 }
294 spin_lock(&inode_lock);
295 inodes_stat.nr_inodes -= nr_disposed;
296 spin_unlock(&inode_lock);
297}
298
299/*
300 * Invalidate all inodes for a device.
301 */
302static int invalidate_list(struct list_head *head, struct list_head *dispose)
303{
304 struct list_head *next;
305 int busy = 0, count = 0;
306
307 next = head->next;
308 for (;;) {
309 struct list_head * tmp = next;
310 struct inode * inode;
311
312 /*
313 * We can reschedule here without worrying about the list's
314 * consistency because the per-sb list of inodes must not
Ingo Molnarf24075b2006-03-23 03:00:34 -0800315 * change during umount anymore, and because iprune_mutex keeps
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 * shrink_icache_memory() away.
317 */
318 cond_resched_lock(&inode_lock);
319
320 next = next->next;
321 if (tmp == head)
322 break;
323 inode = list_entry(tmp, struct inode, i_sb_list);
324 invalidate_inode_buffers(inode);
325 if (!atomic_read(&inode->i_count)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 list_move(&inode->i_list, dispose);
327 inode->i_state |= I_FREEING;
328 count++;
329 continue;
330 }
331 busy = 1;
332 }
333 /* only unused inodes may be cached with i_count zero */
334 inodes_stat.nr_unused -= count;
335 return busy;
336}
337
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338/**
339 * invalidate_inodes - discard the inodes on a device
340 * @sb: superblock
341 *
342 * Discard all of the inodes for a given superblock. If the discard
343 * fails because there are busy inodes then a non zero value is returned.
344 * If the discard is successful all the inodes have been discarded.
345 */
346int invalidate_inodes(struct super_block * sb)
347{
348 int busy;
349 LIST_HEAD(throw_away);
350
Ingo Molnarf24075b2006-03-23 03:00:34 -0800351 mutex_lock(&iprune_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 spin_lock(&inode_lock);
Robert Love0eeca282005-07-12 17:06:03 -0400353 inotify_unmount_inodes(&sb->s_inodes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354 busy = invalidate_list(&sb->s_inodes, &throw_away);
355 spin_unlock(&inode_lock);
356
357 dispose_list(&throw_away);
Ingo Molnarf24075b2006-03-23 03:00:34 -0800358 mutex_unlock(&iprune_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359
360 return busy;
361}
362
363EXPORT_SYMBOL(invalidate_inodes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364
365static int can_unuse(struct inode *inode)
366{
367 if (inode->i_state)
368 return 0;
369 if (inode_has_buffers(inode))
370 return 0;
371 if (atomic_read(&inode->i_count))
372 return 0;
373 if (inode->i_data.nrpages)
374 return 0;
375 return 1;
376}
377
378/*
379 * Scan `goal' inodes on the unused list for freeable ones. They are moved to
380 * a temporary list and then are freed outside inode_lock by dispose_list().
381 *
382 * Any inodes which are pinned purely because of attached pagecache have their
383 * pagecache removed. We expect the final iput() on that inode to add it to
384 * the front of the inode_unused list. So look for it there and if the
385 * inode is still freeable, proceed. The right inode is found 99.9% of the
386 * time in testing on a 4-way.
387 *
388 * If the inode has metadata buffers attached to mapping->private_list then
389 * try to remove them.
390 */
391static void prune_icache(int nr_to_scan)
392{
393 LIST_HEAD(freeable);
394 int nr_pruned = 0;
395 int nr_scanned;
396 unsigned long reap = 0;
397
Ingo Molnarf24075b2006-03-23 03:00:34 -0800398 mutex_lock(&iprune_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399 spin_lock(&inode_lock);
400 for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
401 struct inode *inode;
402
403 if (list_empty(&inode_unused))
404 break;
405
406 inode = list_entry(inode_unused.prev, struct inode, i_list);
407
408 if (inode->i_state || atomic_read(&inode->i_count)) {
409 list_move(&inode->i_list, &inode_unused);
410 continue;
411 }
412 if (inode_has_buffers(inode) || inode->i_data.nrpages) {
413 __iget(inode);
414 spin_unlock(&inode_lock);
415 if (remove_inode_buffers(inode))
Andrew Mortonfc0ecff2007-02-10 01:45:39 -0800416 reap += invalidate_mapping_pages(&inode->i_data,
417 0, -1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 iput(inode);
419 spin_lock(&inode_lock);
420
421 if (inode != list_entry(inode_unused.next,
422 struct inode, i_list))
423 continue; /* wrong inode or list_empty */
424 if (!can_unuse(inode))
425 continue;
426 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 list_move(&inode->i_list, &freeable);
428 inode->i_state |= I_FREEING;
429 nr_pruned++;
430 }
431 inodes_stat.nr_unused -= nr_pruned;
Christoph Lameterf8891e52006-06-30 01:55:45 -0700432 if (current_is_kswapd())
433 __count_vm_events(KSWAPD_INODESTEAL, reap);
434 else
435 __count_vm_events(PGINODESTEAL, reap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436 spin_unlock(&inode_lock);
437
438 dispose_list(&freeable);
Ingo Molnarf24075b2006-03-23 03:00:34 -0800439 mutex_unlock(&iprune_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440}
441
442/*
443 * shrink_icache_memory() will attempt to reclaim some unused inodes. Here,
444 * "unused" means that no dentries are referring to the inodes: the files are
445 * not open and the dcache references to those inodes have already been
446 * reclaimed.
447 *
448 * This function is passed the number of inodes to scan, and it returns the
449 * total number of remaining possibly-reclaimable inodes.
450 */
Al Viro27496a82005-10-21 03:20:48 -0400451static int shrink_icache_memory(int nr, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452{
453 if (nr) {
454 /*
455 * Nasty deadlock avoidance. We may hold various FS locks,
456 * and we don't want to recurse into the FS that called us
457 * in clear_inode() and friends..
458 */
459 if (!(gfp_mask & __GFP_FS))
460 return -1;
461 prune_icache(nr);
462 }
463 return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure;
464}
465
466static void __wait_on_freeing_inode(struct inode *inode);
467/*
468 * Called with the inode lock held.
469 * NOTE: we are not increasing the inode-refcount, you must call __iget()
470 * by hand after calling find_inode now! This simplifies iunique and won't
471 * add any additional branch in the common code.
472 */
473static struct inode * find_inode(struct super_block * sb, struct hlist_head *head, int (*test)(struct inode *, void *), void *data)
474{
475 struct hlist_node *node;
476 struct inode * inode = NULL;
477
478repeat:
479 hlist_for_each (node, head) {
480 inode = hlist_entry(node, struct inode, i_hash);
481 if (inode->i_sb != sb)
482 continue;
483 if (!test(inode, data))
484 continue;
Alexander Viro991114c2005-06-23 00:09:01 -0700485 if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486 __wait_on_freeing_inode(inode);
487 goto repeat;
488 }
489 break;
490 }
491 return node ? inode : NULL;
492}
493
494/*
495 * find_inode_fast is the fast path version of find_inode, see the comment at
496 * iget_locked for details.
497 */
498static struct inode * find_inode_fast(struct super_block * sb, struct hlist_head *head, unsigned long ino)
499{
500 struct hlist_node *node;
501 struct inode * inode = NULL;
502
503repeat:
504 hlist_for_each (node, head) {
505 inode = hlist_entry(node, struct inode, i_hash);
506 if (inode->i_ino != ino)
507 continue;
508 if (inode->i_sb != sb)
509 continue;
Alexander Viro991114c2005-06-23 00:09:01 -0700510 if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 __wait_on_freeing_inode(inode);
512 goto repeat;
513 }
514 break;
515 }
516 return node ? inode : NULL;
517}
518
519/**
520 * new_inode - obtain an inode
521 * @sb: superblock
522 *
523 * Allocates a new inode for given superblock.
524 */
525struct inode *new_inode(struct super_block *sb)
526{
Jeff Layton866b04f2007-05-08 00:32:29 -0700527 /*
528 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
529 * error if st_ino won't fit in target struct field. Use 32bit counter
530 * here to attempt to avoid that.
531 */
532 static unsigned int last_ino;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 struct inode * inode;
534
535 spin_lock_prefetch(&inode_lock);
536
537 inode = alloc_inode(sb);
538 if (inode) {
539 spin_lock(&inode_lock);
540 inodes_stat.nr_inodes++;
541 list_add(&inode->i_list, &inode_in_use);
542 list_add(&inode->i_sb_list, &sb->s_inodes);
543 inode->i_ino = ++last_ino;
544 inode->i_state = 0;
545 spin_unlock(&inode_lock);
546 }
547 return inode;
548}
549
550EXPORT_SYMBOL(new_inode);
551
552void unlock_new_inode(struct inode *inode)
553{
554 /*
555 * This is special! We do not need the spinlock
556 * when clearing I_LOCK, because we're guaranteed
557 * that nobody else tries to do anything about the
558 * state of the inode when it is locked, as we
559 * just created it (so there can be no old holders
560 * that haven't tested I_LOCK).
561 */
562 inode->i_state &= ~(I_LOCK|I_NEW);
563 wake_up_inode(inode);
564}
565
566EXPORT_SYMBOL(unlock_new_inode);
567
568/*
569 * This is called without the inode lock held.. Be careful.
570 *
571 * We no longer cache the sb_flags in i_flags - see fs.h
572 * -- rmk@arm.uk.linux.org
573 */
574static struct inode * get_new_inode(struct super_block *sb, struct hlist_head *head, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *data)
575{
576 struct inode * inode;
577
578 inode = alloc_inode(sb);
579 if (inode) {
580 struct inode * old;
581
582 spin_lock(&inode_lock);
583 /* We released the lock, so.. */
584 old = find_inode(sb, head, test, data);
585 if (!old) {
586 if (set(inode, data))
587 goto set_failed;
588
589 inodes_stat.nr_inodes++;
590 list_add(&inode->i_list, &inode_in_use);
591 list_add(&inode->i_sb_list, &sb->s_inodes);
592 hlist_add_head(&inode->i_hash, head);
593 inode->i_state = I_LOCK|I_NEW;
594 spin_unlock(&inode_lock);
595
596 /* Return the locked inode with I_NEW set, the
597 * caller is responsible for filling in the contents
598 */
599 return inode;
600 }
601
602 /*
603 * Uhhuh, somebody else created the same inode under
604 * us. Use the old inode instead of the one we just
605 * allocated.
606 */
607 __iget(old);
608 spin_unlock(&inode_lock);
609 destroy_inode(inode);
610 inode = old;
611 wait_on_inode(inode);
612 }
613 return inode;
614
615set_failed:
616 spin_unlock(&inode_lock);
617 destroy_inode(inode);
618 return NULL;
619}
620
621/*
622 * get_new_inode_fast is the fast path version of get_new_inode, see the
623 * comment at iget_locked for details.
624 */
625static struct inode * get_new_inode_fast(struct super_block *sb, struct hlist_head *head, unsigned long ino)
626{
627 struct inode * inode;
628
629 inode = alloc_inode(sb);
630 if (inode) {
631 struct inode * old;
632
633 spin_lock(&inode_lock);
634 /* We released the lock, so.. */
635 old = find_inode_fast(sb, head, ino);
636 if (!old) {
637 inode->i_ino = ino;
638 inodes_stat.nr_inodes++;
639 list_add(&inode->i_list, &inode_in_use);
640 list_add(&inode->i_sb_list, &sb->s_inodes);
641 hlist_add_head(&inode->i_hash, head);
642 inode->i_state = I_LOCK|I_NEW;
643 spin_unlock(&inode_lock);
644
645 /* Return the locked inode with I_NEW set, the
646 * caller is responsible for filling in the contents
647 */
648 return inode;
649 }
650
651 /*
652 * Uhhuh, somebody else created the same inode under
653 * us. Use the old inode instead of the one we just
654 * allocated.
655 */
656 __iget(old);
657 spin_unlock(&inode_lock);
658 destroy_inode(inode);
659 inode = old;
660 wait_on_inode(inode);
661 }
662 return inode;
663}
664
Andreas Mohred97bd32006-10-02 02:17:17 -0700665static unsigned long hash(struct super_block *sb, unsigned long hashval)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666{
667 unsigned long tmp;
668
669 tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
670 L1_CACHE_BYTES;
671 tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
672 return tmp & I_HASHMASK;
673}
674
675/**
676 * iunique - get a unique inode number
677 * @sb: superblock
678 * @max_reserved: highest reserved inode number
679 *
680 * Obtain an inode number that is unique on the system for a given
681 * superblock. This is used by file systems that have no natural
682 * permanent inode numbering system. An inode number is returned that
683 * is higher than the reserved limit but unique.
684 *
685 * BUGS:
686 * With a large number of inodes live on the file system this function
687 * currently becomes quite slow.
688 */
689ino_t iunique(struct super_block *sb, ino_t max_reserved)
690{
Jeff Layton866b04f2007-05-08 00:32:29 -0700691 /*
692 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
693 * error if st_ino won't fit in target struct field. Use 32bit counter
694 * here to attempt to avoid that.
695 */
696 static unsigned int counter;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 struct inode *inode;
Jeffrey Layton3361c7b2007-05-08 00:29:48 -0700698 struct hlist_head *head;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699 ino_t res;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700
Jeffrey Layton3361c7b2007-05-08 00:29:48 -0700701 spin_lock(&inode_lock);
702 do {
703 if (counter <= max_reserved)
704 counter = max_reserved + 1;
705 res = counter++;
706 head = inode_hashtable + hash(sb, res);
707 inode = find_inode_fast(sb, head, res);
708 } while (inode != NULL);
709 spin_unlock(&inode_lock);
710
711 return res;
712}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713EXPORT_SYMBOL(iunique);
714
715struct inode *igrab(struct inode *inode)
716{
717 spin_lock(&inode_lock);
Jan Blunck4a3b0a42007-02-10 01:44:59 -0800718 if (!(inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 __iget(inode);
720 else
721 /*
722 * Handle the case where s_op->clear_inode is not been
723 * called yet, and somebody is calling igrab
724 * while the inode is getting freed.
725 */
726 inode = NULL;
727 spin_unlock(&inode_lock);
728 return inode;
729}
730
731EXPORT_SYMBOL(igrab);
732
733/**
734 * ifind - internal function, you want ilookup5() or iget5().
735 * @sb: super block of file system to search
736 * @head: the head of the list to search
737 * @test: callback used for comparisons between inodes
738 * @data: opaque data pointer to pass to @test
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700739 * @wait: if true wait for the inode to be unlocked, if false do not
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740 *
741 * ifind() searches for the inode specified by @data in the inode
742 * cache. This is a generalized version of ifind_fast() for file systems where
743 * the inode number is not sufficient for unique identification of an inode.
744 *
745 * If the inode is in the cache, the inode is returned with an incremented
746 * reference count.
747 *
748 * Otherwise NULL is returned.
749 *
750 * Note, @test is called with the inode_lock held, so can't sleep.
751 */
Matt Mackall5d2bea42006-01-08 01:05:21 -0800752static struct inode *ifind(struct super_block *sb,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 struct hlist_head *head, int (*test)(struct inode *, void *),
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700754 void *data, const int wait)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755{
756 struct inode *inode;
757
758 spin_lock(&inode_lock);
759 inode = find_inode(sb, head, test, data);
760 if (inode) {
761 __iget(inode);
762 spin_unlock(&inode_lock);
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700763 if (likely(wait))
764 wait_on_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765 return inode;
766 }
767 spin_unlock(&inode_lock);
768 return NULL;
769}
770
771/**
772 * ifind_fast - internal function, you want ilookup() or iget().
773 * @sb: super block of file system to search
774 * @head: head of the list to search
775 * @ino: inode number to search for
776 *
777 * ifind_fast() searches for the inode @ino in the inode cache. This is for
778 * file systems where the inode number is sufficient for unique identification
779 * of an inode.
780 *
781 * If the inode is in the cache, the inode is returned with an incremented
782 * reference count.
783 *
784 * Otherwise NULL is returned.
785 */
Matt Mackall5d2bea42006-01-08 01:05:21 -0800786static struct inode *ifind_fast(struct super_block *sb,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700787 struct hlist_head *head, unsigned long ino)
788{
789 struct inode *inode;
790
791 spin_lock(&inode_lock);
792 inode = find_inode_fast(sb, head, ino);
793 if (inode) {
794 __iget(inode);
795 spin_unlock(&inode_lock);
796 wait_on_inode(inode);
797 return inode;
798 }
799 spin_unlock(&inode_lock);
800 return NULL;
801}
802
803/**
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700804 * ilookup5_nowait - search for an inode in the inode cache
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805 * @sb: super block of file system to search
806 * @hashval: hash value (usually inode number) to search for
807 * @test: callback used for comparisons between inodes
808 * @data: opaque data pointer to pass to @test
809 *
810 * ilookup5() uses ifind() to search for the inode specified by @hashval and
811 * @data in the inode cache. This is a generalized version of ilookup() for
812 * file systems where the inode number is not sufficient for unique
813 * identification of an inode.
814 *
815 * If the inode is in the cache, the inode is returned with an incremented
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700816 * reference count. Note, the inode lock is not waited upon so you have to be
817 * very careful what you do with the returned inode. You probably should be
818 * using ilookup5() instead.
819 *
820 * Otherwise NULL is returned.
821 *
822 * Note, @test is called with the inode_lock held, so can't sleep.
823 */
824struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
825 int (*test)(struct inode *, void *), void *data)
826{
827 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
828
829 return ifind(sb, head, test, data, 0);
830}
831
832EXPORT_SYMBOL(ilookup5_nowait);
833
834/**
835 * ilookup5 - search for an inode in the inode cache
836 * @sb: super block of file system to search
837 * @hashval: hash value (usually inode number) to search for
838 * @test: callback used for comparisons between inodes
839 * @data: opaque data pointer to pass to @test
840 *
841 * ilookup5() uses ifind() to search for the inode specified by @hashval and
842 * @data in the inode cache. This is a generalized version of ilookup() for
843 * file systems where the inode number is not sufficient for unique
844 * identification of an inode.
845 *
846 * If the inode is in the cache, the inode lock is waited upon and the inode is
847 * returned with an incremented reference count.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848 *
849 * Otherwise NULL is returned.
850 *
851 * Note, @test is called with the inode_lock held, so can't sleep.
852 */
853struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
854 int (*test)(struct inode *, void *), void *data)
855{
856 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
857
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700858 return ifind(sb, head, test, data, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859}
860
861EXPORT_SYMBOL(ilookup5);
862
863/**
864 * ilookup - search for an inode in the inode cache
865 * @sb: super block of file system to search
866 * @ino: inode number to search for
867 *
868 * ilookup() uses ifind_fast() to search for the inode @ino in the inode cache.
869 * This is for file systems where the inode number is sufficient for unique
870 * identification of an inode.
871 *
872 * If the inode is in the cache, the inode is returned with an incremented
873 * reference count.
874 *
875 * Otherwise NULL is returned.
876 */
877struct inode *ilookup(struct super_block *sb, unsigned long ino)
878{
879 struct hlist_head *head = inode_hashtable + hash(sb, ino);
880
881 return ifind_fast(sb, head, ino);
882}
883
884EXPORT_SYMBOL(ilookup);
885
886/**
887 * iget5_locked - obtain an inode from a mounted file system
888 * @sb: super block of file system
889 * @hashval: hash value (usually inode number) to get
890 * @test: callback used for comparisons between inodes
891 * @set: callback used to initialize a new struct inode
892 * @data: opaque data pointer to pass to @test and @set
893 *
894 * This is iget() without the read_inode() portion of get_new_inode().
895 *
896 * iget5_locked() uses ifind() to search for the inode specified by @hashval
897 * and @data in the inode cache and if present it is returned with an increased
898 * reference count. This is a generalized version of iget_locked() for file
899 * systems where the inode number is not sufficient for unique identification
900 * of an inode.
901 *
902 * If the inode is not in cache, get_new_inode() is called to allocate a new
903 * inode and this is returned locked, hashed, and with the I_NEW flag set. The
904 * file system gets to fill it in before unlocking it via unlock_new_inode().
905 *
906 * Note both @test and @set are called with the inode_lock held, so can't sleep.
907 */
908struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
909 int (*test)(struct inode *, void *),
910 int (*set)(struct inode *, void *), void *data)
911{
912 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
913 struct inode *inode;
914
Anton Altaparmakov88bd5122005-07-13 01:10:44 -0700915 inode = ifind(sb, head, test, data, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916 if (inode)
917 return inode;
918 /*
919 * get_new_inode() will do the right thing, re-trying the search
920 * in case it had to block at any point.
921 */
922 return get_new_inode(sb, head, test, set, data);
923}
924
925EXPORT_SYMBOL(iget5_locked);
926
927/**
928 * iget_locked - obtain an inode from a mounted file system
929 * @sb: super block of file system
930 * @ino: inode number to get
931 *
932 * This is iget() without the read_inode() portion of get_new_inode_fast().
933 *
934 * iget_locked() uses ifind_fast() to search for the inode specified by @ino in
935 * the inode cache and if present it is returned with an increased reference
936 * count. This is for file systems where the inode number is sufficient for
937 * unique identification of an inode.
938 *
939 * If the inode is not in cache, get_new_inode_fast() is called to allocate a
940 * new inode and this is returned locked, hashed, and with the I_NEW flag set.
941 * The file system gets to fill it in before unlocking it via
942 * unlock_new_inode().
943 */
944struct inode *iget_locked(struct super_block *sb, unsigned long ino)
945{
946 struct hlist_head *head = inode_hashtable + hash(sb, ino);
947 struct inode *inode;
948
949 inode = ifind_fast(sb, head, ino);
950 if (inode)
951 return inode;
952 /*
953 * get_new_inode_fast() will do the right thing, re-trying the search
954 * in case it had to block at any point.
955 */
956 return get_new_inode_fast(sb, head, ino);
957}
958
959EXPORT_SYMBOL(iget_locked);
960
961/**
962 * __insert_inode_hash - hash an inode
963 * @inode: unhashed inode
964 * @hashval: unsigned long value used to locate this object in the
965 * inode_hashtable.
966 *
967 * Add an inode to the inode hash for this superblock.
968 */
969void __insert_inode_hash(struct inode *inode, unsigned long hashval)
970{
971 struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
972 spin_lock(&inode_lock);
973 hlist_add_head(&inode->i_hash, head);
974 spin_unlock(&inode_lock);
975}
976
977EXPORT_SYMBOL(__insert_inode_hash);
978
979/**
980 * remove_inode_hash - remove an inode from the hash
981 * @inode: inode to unhash
982 *
983 * Remove an inode from the superblock.
984 */
985void remove_inode_hash(struct inode *inode)
986{
987 spin_lock(&inode_lock);
988 hlist_del_init(&inode->i_hash);
989 spin_unlock(&inode_lock);
990}
991
992EXPORT_SYMBOL(remove_inode_hash);
993
994/*
995 * Tell the filesystem that this inode is no longer of any interest and should
996 * be completely destroyed.
997 *
998 * We leave the inode in the inode hash table until *after* the filesystem's
999 * ->delete_inode completes. This ensures that an iget (such as nfsd might
1000 * instigate) will always find up-to-date information either in the hash or on
1001 * disk.
1002 *
1003 * I_FREEING is set so that no-one will take a new reference to the inode while
1004 * it is being deleted.
1005 */
1006void generic_delete_inode(struct inode *inode)
1007{
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -08001008 const struct super_operations *op = inode->i_sb->s_op;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009
1010 list_del_init(&inode->i_list);
1011 list_del_init(&inode->i_sb_list);
Andreas Mohred97bd32006-10-02 02:17:17 -07001012 inode->i_state |= I_FREEING;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001013 inodes_stat.nr_inodes--;
1014 spin_unlock(&inode_lock);
1015
Linus Torvalds1da177e2005-04-16 15:20:36 -07001016 security_inode_delete(inode);
1017
1018 if (op->delete_inode) {
1019 void (*delete)(struct inode *) = op->delete_inode;
1020 if (!is_bad_inode(inode))
1021 DQUOT_INIT(inode);
Mark Fashehe85b5652005-09-09 13:01:29 -07001022 /* Filesystems implementing their own
1023 * s_op->delete_inode are required to call
1024 * truncate_inode_pages and clear_inode()
1025 * internally */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001026 delete(inode);
Mark Fashehe85b5652005-09-09 13:01:29 -07001027 } else {
1028 truncate_inode_pages(&inode->i_data, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001029 clear_inode(inode);
Mark Fashehe85b5652005-09-09 13:01:29 -07001030 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031 spin_lock(&inode_lock);
1032 hlist_del_init(&inode->i_hash);
1033 spin_unlock(&inode_lock);
1034 wake_up_inode(inode);
Eric Sesterhennb7542f82006-04-02 13:38:18 +02001035 BUG_ON(inode->i_state != I_CLEAR);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036 destroy_inode(inode);
1037}
1038
1039EXPORT_SYMBOL(generic_delete_inode);
1040
1041static void generic_forget_inode(struct inode *inode)
1042{
1043 struct super_block *sb = inode->i_sb;
1044
1045 if (!hlist_unhashed(&inode->i_hash)) {
1046 if (!(inode->i_state & (I_DIRTY|I_LOCK)))
1047 list_move(&inode->i_list, &inode_unused);
1048 inodes_stat.nr_unused++;
Christoph Hellwigacb0c852007-05-08 00:25:52 -07001049 if (sb->s_flags & MS_ACTIVE) {
Alexander Viro991114c2005-06-23 00:09:01 -07001050 spin_unlock(&inode_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001051 return;
Alexander Viro991114c2005-06-23 00:09:01 -07001052 }
1053 inode->i_state |= I_WILL_FREE;
1054 spin_unlock(&inode_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001055 write_inode_now(inode, 1);
1056 spin_lock(&inode_lock);
Alexander Viro991114c2005-06-23 00:09:01 -07001057 inode->i_state &= ~I_WILL_FREE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001058 inodes_stat.nr_unused--;
1059 hlist_del_init(&inode->i_hash);
1060 }
1061 list_del_init(&inode->i_list);
1062 list_del_init(&inode->i_sb_list);
Alexander Viro991114c2005-06-23 00:09:01 -07001063 inode->i_state |= I_FREEING;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001064 inodes_stat.nr_inodes--;
1065 spin_unlock(&inode_lock);
1066 if (inode->i_data.nrpages)
1067 truncate_inode_pages(&inode->i_data, 0);
1068 clear_inode(inode);
Andrea Arcangeli7f04c262005-10-30 15:03:05 -08001069 wake_up_inode(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001070 destroy_inode(inode);
1071}
1072
1073/*
1074 * Normal UNIX filesystem behaviour: delete the
1075 * inode when the usage count drops to zero, and
1076 * i_nlink is zero.
1077 */
Mark Fashehcb2c0232005-07-07 17:56:03 -07001078void generic_drop_inode(struct inode *inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001079{
1080 if (!inode->i_nlink)
1081 generic_delete_inode(inode);
1082 else
1083 generic_forget_inode(inode);
1084}
1085
Mark Fashehcb2c0232005-07-07 17:56:03 -07001086EXPORT_SYMBOL_GPL(generic_drop_inode);
1087
Linus Torvalds1da177e2005-04-16 15:20:36 -07001088/*
1089 * Called when we're dropping the last reference
1090 * to an inode.
1091 *
1092 * Call the FS "drop()" function, defaulting to
1093 * the legacy UNIX filesystem behaviour..
1094 *
1095 * NOTE! NOTE! NOTE! We're called with the inode lock
1096 * held, and the drop function is supposed to release
1097 * the lock!
1098 */
1099static inline void iput_final(struct inode *inode)
1100{
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -08001101 const struct super_operations *op = inode->i_sb->s_op;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001102 void (*drop)(struct inode *) = generic_drop_inode;
1103
1104 if (op && op->drop_inode)
1105 drop = op->drop_inode;
1106 drop(inode);
1107}
1108
1109/**
1110 * iput - put an inode
1111 * @inode: inode to put
1112 *
1113 * Puts an inode, dropping its usage count. If the inode use count hits
1114 * zero, the inode is then freed and may also be destroyed.
1115 *
1116 * Consequently, iput() can sleep.
1117 */
1118void iput(struct inode *inode)
1119{
1120 if (inode) {
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -08001121 const struct super_operations *op = inode->i_sb->s_op;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001122
1123 BUG_ON(inode->i_state == I_CLEAR);
1124
1125 if (op && op->put_inode)
1126 op->put_inode(inode);
1127
1128 if (atomic_dec_and_lock(&inode->i_count, &inode_lock))
1129 iput_final(inode);
1130 }
1131}
1132
1133EXPORT_SYMBOL(iput);
1134
1135/**
1136 * bmap - find a block number in a file
1137 * @inode: inode of file
1138 * @block: block to find
1139 *
1140 * Returns the block number on the device holding the inode that
1141 * is the disk block number for the block of the file requested.
1142 * That is, asked for block 4 of inode 1 the function will return the
1143 * disk block relative to the disk start that holds that block of the
1144 * file.
1145 */
1146sector_t bmap(struct inode * inode, sector_t block)
1147{
1148 sector_t res = 0;
1149 if (inode->i_mapping->a_ops->bmap)
1150 res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
1151 return res;
1152}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153EXPORT_SYMBOL(bmap);
1154
1155/**
Christoph Hellwig869243a2006-01-09 20:52:03 -08001156 * touch_atime - update the access time
1157 * @mnt: mount the inode is accessed on
Martin Waitz7045f372006-02-01 03:06:57 -08001158 * @dentry: dentry accessed
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159 *
1160 * Update the accessed time on an inode and mark it for writeback.
1161 * This function automatically handles read only file systems and media,
1162 * as well as the "noatime" flag and inode specific "noatime" markers.
1163 */
Christoph Hellwig869243a2006-01-09 20:52:03 -08001164void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001165{
Christoph Hellwig869243a2006-01-09 20:52:03 -08001166 struct inode *inode = dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001167 struct timespec now;
1168
Andrew Mortonb2276132006-12-13 00:34:33 -08001169 if (inode->i_flags & S_NOATIME)
1170 return;
Eric Dumazet37756ce2007-02-10 01:44:49 -08001171 if (IS_NOATIME(inode))
Andrew Mortonb2276132006-12-13 00:34:33 -08001172 return;
1173 if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode))
Christoph Hellwigfc33a7b2006-01-09 20:52:17 -08001174 return;
1175
1176 /*
1177 * We may have a NULL vfsmount when coming from NFSD
1178 */
Andrew Mortonb2276132006-12-13 00:34:33 -08001179 if (mnt) {
1180 if (mnt->mnt_flags & MNT_NOATIME)
1181 return;
1182 if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
1183 return;
Valerie Henson47ae32d2006-12-13 00:34:34 -08001184
1185 if (mnt->mnt_flags & MNT_RELATIME) {
1186 /*
1187 * With relative atime, only update atime if the
1188 * previous atime is earlier than either the ctime or
1189 * mtime.
1190 */
1191 if (timespec_compare(&inode->i_mtime,
1192 &inode->i_atime) < 0 &&
1193 timespec_compare(&inode->i_ctime,
1194 &inode->i_atime) < 0)
1195 return;
1196 }
Andrew Mortonb2276132006-12-13 00:34:33 -08001197 }
Christoph Hellwigfc33a7b2006-01-09 20:52:17 -08001198
Linus Torvalds1da177e2005-04-16 15:20:36 -07001199 now = current_fs_time(inode->i_sb);
Valerie Henson47ae32d2006-12-13 00:34:34 -08001200 if (timespec_equal(&inode->i_atime, &now))
1201 return;
1202
1203 inode->i_atime = now;
1204 mark_inode_dirty_sync(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205}
Christoph Hellwig869243a2006-01-09 20:52:03 -08001206EXPORT_SYMBOL(touch_atime);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207
1208/**
Christoph Hellwig870f4812006-01-09 20:52:01 -08001209 * file_update_time - update mtime and ctime time
1210 * @file: file accessed
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211 *
Christoph Hellwig870f4812006-01-09 20:52:01 -08001212 * Update the mtime and ctime members of an inode and mark the inode
1213 * for writeback. Note that this function is meant exclusively for
1214 * usage in the file write path of filesystems, and filesystems may
1215 * choose to explicitly ignore update via this function with the
1216 * S_NOCTIME inode flag, e.g. for network filesystem where these
1217 * timestamps are handled by the server.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001218 */
1219
Christoph Hellwig870f4812006-01-09 20:52:01 -08001220void file_update_time(struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221{
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001222 struct inode *inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001223 struct timespec now;
1224 int sync_it = 0;
1225
1226 if (IS_NOCMTIME(inode))
1227 return;
1228 if (IS_RDONLY(inode))
1229 return;
1230
1231 now = current_fs_time(inode->i_sb);
Andreas Mohred97bd32006-10-02 02:17:17 -07001232 if (!timespec_equal(&inode->i_mtime, &now)) {
1233 inode->i_mtime = now;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001234 sync_it = 1;
Andreas Mohred97bd32006-10-02 02:17:17 -07001235 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001236
Andreas Mohred97bd32006-10-02 02:17:17 -07001237 if (!timespec_equal(&inode->i_ctime, &now)) {
1238 inode->i_ctime = now;
Christoph Hellwig870f4812006-01-09 20:52:01 -08001239 sync_it = 1;
Andreas Mohred97bd32006-10-02 02:17:17 -07001240 }
Christoph Hellwig870f4812006-01-09 20:52:01 -08001241
Linus Torvalds1da177e2005-04-16 15:20:36 -07001242 if (sync_it)
1243 mark_inode_dirty_sync(inode);
1244}
1245
Christoph Hellwig870f4812006-01-09 20:52:01 -08001246EXPORT_SYMBOL(file_update_time);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001247
1248int inode_needs_sync(struct inode *inode)
1249{
1250 if (IS_SYNC(inode))
1251 return 1;
1252 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
1253 return 1;
1254 return 0;
1255}
1256
1257EXPORT_SYMBOL(inode_needs_sync);
1258
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259int inode_wait(void *word)
1260{
1261 schedule();
1262 return 0;
1263}
1264
1265/*
Miklos Szeredi168a9fd2005-07-12 13:58:10 -07001266 * If we try to find an inode in the inode hash while it is being
1267 * deleted, we have to wait until the filesystem completes its
1268 * deletion before reporting that it isn't found. This function waits
1269 * until the deletion _might_ have completed. Callers are responsible
1270 * to recheck inode state.
1271 *
1272 * It doesn't matter if I_LOCK is not set initially, a call to
1273 * wake_up_inode() after removing from the hash list will DTRT.
1274 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275 * This is called with inode_lock held.
1276 */
1277static void __wait_on_freeing_inode(struct inode *inode)
1278{
1279 wait_queue_head_t *wq;
1280 DEFINE_WAIT_BIT(wait, &inode->i_state, __I_LOCK);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001281 wq = bit_waitqueue(&inode->i_state, __I_LOCK);
1282 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
1283 spin_unlock(&inode_lock);
1284 schedule();
1285 finish_wait(wq, &wait.wait);
1286 spin_lock(&inode_lock);
1287}
1288
1289void wake_up_inode(struct inode *inode)
1290{
1291 /*
1292 * Prevent speculative execution through spin_unlock(&inode_lock);
1293 */
1294 smp_mb();
1295 wake_up_bit(&inode->i_state, __I_LOCK);
1296}
1297
Mark Fasheh62752ee2006-10-17 10:31:38 +02001298/*
1299 * We rarely want to lock two inodes that do not have a parent/child
1300 * relationship (such as directory, child inode) simultaneously. The
1301 * vast majority of file systems should be able to get along fine
1302 * without this. Do not use these functions except as a last resort.
1303 */
1304void inode_double_lock(struct inode *inode1, struct inode *inode2)
1305{
1306 if (inode1 == NULL || inode2 == NULL || inode1 == inode2) {
1307 if (inode1)
1308 mutex_lock(&inode1->i_mutex);
1309 else if (inode2)
1310 mutex_lock(&inode2->i_mutex);
1311 return;
1312 }
1313
1314 if (inode1 < inode2) {
1315 mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT);
1316 mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
1317 } else {
1318 mutex_lock_nested(&inode2->i_mutex, I_MUTEX_PARENT);
1319 mutex_lock_nested(&inode1->i_mutex, I_MUTEX_CHILD);
1320 }
1321}
1322EXPORT_SYMBOL(inode_double_lock);
1323
1324void inode_double_unlock(struct inode *inode1, struct inode *inode2)
1325{
1326 if (inode1)
1327 mutex_unlock(&inode1->i_mutex);
1328
1329 if (inode2 && inode2 != inode1)
1330 mutex_unlock(&inode2->i_mutex);
1331}
1332EXPORT_SYMBOL(inode_double_unlock);
1333
Linus Torvalds1da177e2005-04-16 15:20:36 -07001334static __initdata unsigned long ihash_entries;
1335static int __init set_ihash_entries(char *str)
1336{
1337 if (!str)
1338 return 0;
1339 ihash_entries = simple_strtoul(str, &str, 0);
1340 return 1;
1341}
1342__setup("ihash_entries=", set_ihash_entries);
1343
1344/*
1345 * Initialize the waitqueues and inode hash table.
1346 */
1347void __init inode_init_early(void)
1348{
1349 int loop;
1350
1351 /* If hashes are distributed across NUMA nodes, defer
1352 * hash allocation until vmalloc space is available.
1353 */
1354 if (hashdist)
1355 return;
1356
1357 inode_hashtable =
1358 alloc_large_system_hash("Inode-cache",
1359 sizeof(struct hlist_head),
1360 ihash_entries,
1361 14,
1362 HASH_EARLY,
1363 &i_hash_shift,
1364 &i_hash_mask,
1365 0);
1366
1367 for (loop = 0; loop < (1 << i_hash_shift); loop++)
1368 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1369}
1370
1371void __init inode_init(unsigned long mempages)
1372{
1373 int loop;
1374
1375 /* inode slab cache */
Paul Jacksonb0196002006-03-24 03:16:09 -08001376 inode_cachep = kmem_cache_create("inode_cache",
1377 sizeof(struct inode),
1378 0,
1379 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
1380 SLAB_MEM_SPREAD),
1381 init_once,
1382 NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001383 set_shrinker(DEFAULT_SEEKS, shrink_icache_memory);
1384
1385 /* Hash may have been set up in inode_init_early */
1386 if (!hashdist)
1387 return;
1388
1389 inode_hashtable =
1390 alloc_large_system_hash("Inode-cache",
1391 sizeof(struct hlist_head),
1392 ihash_entries,
1393 14,
1394 0,
1395 &i_hash_shift,
1396 &i_hash_mask,
1397 0);
1398
1399 for (loop = 0; loop < (1 << i_hash_shift); loop++)
1400 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1401}
1402
1403void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
1404{
1405 inode->i_mode = mode;
1406 if (S_ISCHR(mode)) {
1407 inode->i_fop = &def_chr_fops;
1408 inode->i_rdev = rdev;
1409 } else if (S_ISBLK(mode)) {
1410 inode->i_fop = &def_blk_fops;
1411 inode->i_rdev = rdev;
1412 } else if (S_ISFIFO(mode))
1413 inode->i_fop = &def_fifo_fops;
1414 else if (S_ISSOCK(mode))
1415 inode->i_fop = &bad_sock_fops;
1416 else
1417 printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o)\n",
1418 mode);
1419}
1420EXPORT_SYMBOL(init_special_inode);